The Clondalkin man, who is aged in his 20s, was arrested when gardaí raided a house at 8.30pm and discovered two men bagging the cocaine haul in a downstairs room.

Gilligan's close associate is understood to have spent a lot of time with the veteran crimelord in the months after he was released from Portlaoise Prison in October 2013.

As well as Gilligan's close associate, another man, who is his 30s, was also arrested and the duo are being questioned today at Ronanstown and Lucan Garda stations.

When officers searched the attic of the raided house, they discovered two 9mm pistols, two silencers and ammunition.

Sources say that the arrested young man has been a target for detectives in west Dublin for years and is closely associated with a double killer from Neilstown who is currently on remand in prison.

The arrested man also has close links to John Gilligan's brother Thomas. It was at Thomas's house in Greenfort Crescent, Clondalkin, on March 1, last year that Gilligan was shot at numerous times.

After being released from Portlaoise Prison over two years ago, Gilligan survived two attempts on his life.

It is understood Gilligan is still living between his extended family, based between Birmingham and London, and occasionally staying in Traveller halting sites with criminals linked to the McCarthy/Dundon gang.